Abstract: A dispatch controller (103) located logically external to an existing telephone network (101) is coupled to the existing telephone network. When an originating communication device (e.g., 111) desires to initiate a dispatch call, the originating device transmits a call request to the existing telephone network, wherein the call request includes an identification (ID) of the originating device and a target address associated with the dispatch controller. The existing telephone network provides the call request to the dispatch controller. Upon receiving the call request, the dispatch controller retrieves dispatch-related information from a database (105) coupled to the dispatch controller based on the originating device's ID. Based on the retrieved dispatch-related information, the dispatch controller identifies a group of target communication devices (e.g., 107-110) for the dispatch call.

Abstract: A calling communication unit (210) transmits a dispatch communication request to a communication infrastructure (202). The dispatch communication request includes at least a dispatch identification of a called communication unit (e.g., 216). In response to the dispatch communication request, the calling communication unit receives from the communication infrastructure a telephone number associated with a voice mail server (222) that provides voice mail service to the called communication unit and an identification of a mailbox at the voice mail server. The calling communication unit then transmits to the voice mail server the identification of the mailbox and a voice communication. Finally, the voice mail server stores the voice communication in the mailbox.

Abstract: A dispatch controller (103) located logically external to an existing telephone network (101) is coupled to the existing telephone network. When an originating communication device (e.g., 111) desires to initiate a dispatch call, the originating device transmits a call request to the existing telephone network, wherein the call request includes an identification (ID) of the originating device and a target address associated with the dispatch controller. The existing telephone network provides the call request to the dispatch controller. Upon receiving the call request, the dispatch controller retrieves dispatch-related information from a database (105) coupled to the dispatch controller based on the originating device's ID. Based on the retrieved dispatch-related information, the dispatch controller identifies a group of target communication devices (e.g., 107-110) for the dispatch call.

Abstract: A system for networking dispatch-type of communications. A plurality of radio cells are coupled to a centralized hub controller via the public switched telephone network. The radio cells are networked together via the hub controller using one or more telephone voice lines and a respective data line for providing communications between each radio cell and the hub controller. Data packets are transferred between the radio cells and the hub controller on the data lines to set up a path for the dispatch communications on the telephone voice lines. The hub controller carries out a trunking function of the telephone voice lines so that the number of voice lines are minimized, while yet preventing blocking of dispatch communications.

Abstract: A method and apparatus of linking communication systems of different types. Call requests are directed from a sourcing communication unit in a first communication system (101) to a gateway (114), which translates identity and call type information from the first system to at least one other system (113). Next, the gateway requests radio frequency (RF) resources from each system to support the call. After sufficient RF resources have been received, and prior to the sourcing communication unit starting a call, the gateway (114) issues call start information to each of the communication systems (101, 113). Then, the gateway (114) is operable to receive and translate a message payload from the sourcing communication unit and distribute the translated message payload to communication units in the at least one other system.

Abstract: A subscriber (510) to a radio communication system acquires new neighbor cell information after switching to a new server site (530) during lulls in an ongoing communication session. In one embodiment, the new server site (530) broadcasts neighbor cell list information during lulls in the communication activity on the communication channel in an unsolicited manner (710, 720). In an alternative embodiment, the subscriber (510) first transmits a request to the server site for neighbor cell list information during a lull in communication activity (810, 820). The server site (530) responds by transmitting neighbor cell list information during one or more lulls in communication activity on the communication channel (830, 840).

Abstract: A method for maintaining a group call in a mobile radio system, and a mobile station in a mobile radio system, wherein the geographical area covered by the system is divided into radio cells. Each radio cell includes a base station. A group call is established between the mobile stations belonging to a group call group and residing within the areas of the radio cells forming a limited group call area. In order that the mobile station, upon changing radio cells, is able to select the base station within the area of which the group call is in progress, the respective base stations send one or a plurality of group call maintenance messages to the mobile stations involved in the group call. The group call maintenance message contains information concerning the base stations located within the areas of the radio cells forming the group call area, and the group call group identity.

Abstract: A communication method is provided in which mobiles operating in a trunk mode operation transmit a message on a direct mode operation channel indicating a trunk mode operation connection is present. If a mobile outside the range of coverage of the trunking system receives the message it will deduce from the message the slot structure of the trunk mode channel and its timing, and will then be able to transmit a request for a direct mode connection on an appropriate slot of the trunk mode channel. Some or all of the mobiles operating in trunk mode will then be able to switch to direct mode to connect with the mobile outside the range of coverage.

Abstract: A radio communication system includes a plurality of sites that each belong to one of a plurality of zones. The plurality of zones are each linked to a zone controller and the plurality of sites are employed to facilitate communications among a plurality of communication units affiliated therewith. A method of establishing a communication between two of the plurality of communication units that are presently affiliated with sites not belonging to a common zone includes the step of determining a preferred zone for at least one of the plurality of communication units. After identifying a usable site that belongs to the preferred zone, the communication unit then affiliates with the usable site to facilitate the communications with the second communication unit.

Abstract: A method and apparatus for passively monitoring communications in a trunked communication system. Digital messages transmitted over a control channel at a particular frequency are monitored with a receiver. When a first bit pattern is detected in a digital message, subsequently transmitted data is stored. Information is extracted from the stored data to obtain a channel assignment code indicating a frequency over which communications take place and a talk group identification code identifying a talk group in the trunked communication system participating in a communication. If the talk group is a talk group of interest, the receiver is tuned to the frequency corresponding to the channel assignment code so that voice communications are successfully monitored.

Abstract: A radio (101) affiliates with radio frequency sites (135, 145) based on a radio database (110) defining a group of valid site affiliations and a group of invalid site affiliations. Affiliations by the radio are controlled by a controller (120) with a controller database (160) defining a group of allowed site affiliations and a group of non-allowed site affiliations. When the controller database is altered, the radio database is updated to match the altered controller database. When the controller adds a site to its group of allowed site affiliations, it sends an updated radio database to the radio. When the controller adds a site to its group of non-allowed site affiliations, it waits until the radio requests permission to affiliate with that site and then sends an updated radio database to the radio. Upon receipt, the radio replaces its existing radio database with the updated radio database.

Abstract: For establishing an expanded group call in a mobile communication system which has group call groups formed by a plurality of mobile stations, a network infrastructure which has at least one exchange, a plurality of base stations and telecommunication connections between them, and a group call database for maintaining data concerning group calls, an expanded group call set-up facility concerning a first group call group is activated in the group call database, the facility expanding the group call o concern at least one other group call group.

Abstract: A method of handling busy calls, performed by a controlling entity (ZC1) in a multiple-zone system, includes the steps of issuing (201) a request to participate in a call to one or more participating zones (101, 103, and 105) and concluding (203) that at least one zone of the participating zones (101, 103, and 105) is unable to grant the call, thereby resulting in a busy status for the call. The controlling entity (ZC1) informs the participating zones (101, 103 and 105) of the busy status. A resource available notification is received (209) from a first zone, and the controlling entity (ZC1) determines (211) if a predetermined number of the participating zones (101, 103, and 105) have indicated ability to grant the call. When at least one zone of the one or more participating zones has not indicated ability to grant the call, the controlling entity (ZC1) issues (213) a still busy notification to the first zone, which still busy notification indicates that the call still has a busy status.

Abstract: A method and apparatus for providing priority access for users in a transmission trunked communication system, including a plurality of distributive radio network terminal (RNT) switches and a unique signaling protocol and a switching protocol especially adapted for communication of control signals in the subaudio band for interconnecting the trunked transmission communications systems into a wide area network that provides an expanded feature set of radio communications capabilities.

Abstract: Base stations located at physically separate, remote locations are operated as a single site to permit trunked radio communications between portable radios located at those split sites. A first trunked RF communication site located at a first split site location includes plural first base stations, each first base station including a transceiver corresponding to an RF communications channel. The first site also includes a first site controller, connected to each of the first base stations, for assigning base station transceivers to radios requesting an RF communications channel. A second trunked RF communications site is located at a second split site location remote from the first split site location and includes plural second base stations along with a second site controller.

Abstract: Network access delays are minimized by using affiliation messages to pre-establish communications in a wireless communication network (100). In a first embodiment, connections between a site and a multicast server are not pre-assigned. A controller (102), upon receiving an affiliation message from a site (104), establishes connections between the site and a multicast server (111), the connections being uniquely associated with a talkgroup/site affiliation indicated by the affiliation message. In a second embodiment, connections between the site and the multicast server are pre-arranged. Thus, responsive to the affiliation message received from the site, the controller informs the multicast server that a talkgroup is affiliated with the site. Regardless of whether the first or second embodiment is used, the multicast server routes packetized information corresponding to the talkgroup to those sites with which the talkgroup is affiliated.

Abstract: In a digitally trunked radio repeating system that includes several radio repeating transceiver sites linked by a multisite switch, a method for locating a mobile radio when two or more of the sites report having the mobile radio in their site area. When a site reports to the multisite switch that a mobile radio has newly entered the area for the site, the switch broadcasts communications from the mobile radio to two or more sites during a prescribed period of time. If no other site reports receiving a message from the mobile radio during the prescribed period, the radio is logged out of its former site and broadcasts to the radio are only made from the new site. If two or more sites report having the mobile radio in their areas within the prescribed period, a polling method is executed where each of the sites reporting messages from the mobile radio transmits in sequence a command for the mobile radio to respond.

Abstract: A dispatcher console for use in a digitally trunked, multisite public service radio system. The dispatcher counsel comprises a personal computer having a co-processor logic board, an audio switching tower, and user I/Os including a customized keyboard, display screen, audio speakers, headset and a transmit foot pedal. The switching tower routes audio communications between the console and multisite switch. The tower is controlled by and connected directly to the co-processor board. The customized keyboard is also connected directly to the co-processor board and has dedicated keys for commonly performed functions. The display screen presents information in a standard format such that the dispatcher knows precisely where to find particular information.

Abstract: A multi-site communication system (100) includes a plurality of communication units (106, 107) roaming among communication sites (108-111). The communication sites (108-111) are controlled by a central controller (100), via repeaters (102-105), and are thereby capable of establishing communication among sites. A method for minimizing message interruptions during a hand-off, of a first communication unit between two sites, includes the step of receiving (200) a message (300) from a second communication unit. During the message (300), which may be delivered at varying information rates, the first communication unit determines (202) the signal quality. If the signal quality of the message is unfavorable, the receiving communication unit determines (204) when the varying information rate of the message is favorable for a hand-off. Lastly, when the varying information rate is favorable for a hand-off, the first communication unit requests (205) the hand-off.

Abstract: A dispatch radio communication system (100) that includes a dispatch processor (101) and a voice mail system (103) employs a method and apparatus for providing voice mail service in the dispatch system. The dispatch processor receives a request to communicate from a first communication unit (109), wherein the request includes a dispatch identification (ID) of a second communication unit (110) that is a target of a communication from the first communication unit. The dispatch processor then determines whether the second communication unit can participate in the communication. When the second communication unit cannot participate, the dispatch processor establishes a communication path (122, 126) between the first communication unit and a third communication unit (111) that is coupled to the voice mail system to allow a user of the first communication unit to provide a voice mail message to the voice mail system for a user of the second communication unit.

Abstract: The present invention encompasses a method of reconfiguring a distributed communication system (100). A typical distributed communication system (100) includes a plurality of repeaters (102-106) connected via a LAN (108, 110). When a repeater that is acting as an active master (104) receives a Trunking Status Pulse (118), the active master (104) will compare the status information in the received TSP (118) with the present status information to determine which active master is the favorable active master. The active master with the favorable present resource allocation loading level will continue to operate as the active master, while the active with the least favorable present resource allocation loading level will relinquish control as an active master.

Abstract: A method for resolving talk group call contention in a multi-site trunked radio frequency communications network is accomplished in a distributed manner by utilizing autonomous call arbitration processes at each interface node to avoid potential performance bottlenecking and a "single point of failure" configuration that would arise in a conventional centralized arbitration arrangement. Call contention in a multi-site environment occurs when multiple callers at different sites attempt to transmit on a common talk group at nearly the same moment. The call processing system that coordinates communications between sites must resolve this contention to ensure that the transmission is processed consistently at all sites. In accordance with the distributed manner of the present invention, each site interface autonomously determines which call should be given priority in a contention situation based upon a predetermined common set of arbitration "rules".

Abstract: In an extended overall radio communications network, one or more dedicated Network Interface Modules (NIMs) are provided in each multisite trunked communications systems to permit the interconnection and communication between plural, multisite systems. A remote multisite system appears through the local NIM as just another site interface to the local multisite system. Basic and advanced dispatch console functions are effected over the extended network via the NIMs in a manner that is transparent to the console operator.

Abstract: A central networker interface is used to establish inter-operability between a conventional communication system and a trunked communication system. The central networker interface provides the conventional communication system with wireline and RF connections to the trunked communication system. These connections allow each system to share information pertaining to communication units operating within their respective coverage areas.